Bone Pathology Flashcards

Question 1

Q

Secondary

Bone Tumors

Answer

A

Metastatic tumors
- Most frequent malignant tumors found in bone
- Predominant occurrence in adults > 40 yrs and children in first decade of life
- Multifocal
- Predilection for the marrow in the axial skeleton (vertebrae, pelvis, ribs and cranium) and proximal long bones
Tumors resulting from contiguous spread of adjacent soft tissue neoplasms

Question 2

Q

Metastatic Origins

Answer

A

Most common malignancies producing skeletal metastases:

Adults:
- Prostate, breast, kidney, and lung
- Thyroid and colon cancers
- Melanoma
Children:
- Neuroblastoma
- Rhabdomyosarcoma
- Retinoblastoma

Question 3

Q

Osteoarticular System

Primary Tumors

Answer

A

Relatively uncommon ⇒ 2,400 cases of primary bone sarcoma/year in US
Benign tumors more common
Occur mostly in the first three decades of life
Clinical hx including age, location of tumor and radiological data are very important to diagnosis

Question 4

Q

Most Common

Benign Tumors

Answer

A

Osteochondroma
Non-ossifying fibroma
Enchondroma

Question 5

Q

Most Common

Malignant Tumors

Answer

A

Excluding malignant neoplasms of marrow origin:

Osteosarcoma
Chondrosarcoma
Ewings sarcoma

Question 6

Q

Bone Tumors

Features

Answer

A

Some able to dedifferentiate
- eg., enchondroma or a low-grade chondrosarcoma transforming into a high-grade sarcoma
Tendency of high-grade sarcomas to arise in damaged bone
- Sites of bone infarcts
- Radiation osteitis
- Paget’s disease

Question 7

Q

Primary Bone Tumor

Classifications

Question 8

Q

Age of Onset

Answer

A

Predominant occurrence in first 3 decades of life

Question 9

Q

Common Tumors

Ages 0-10

Question 10

Q

Common Tumors

Ages 10-20

Question 11

Q

Common Tumors

Ages 20-40

Question 12

Q

Common Tumors

Ages 40+

Question 13

Q

Bone Tumor

Frequent Locations

Answer

A

Distal femur and proximal tibia most common
- Both benign and malignant
- Bones with highest growth rate
Many lesions favor certain bones or sites

Question 14

Q

Bone Tumors

Location Preference

Question 15

Q

Bone Tumors

Imaging Studies

Answer

A

Most bone tumors have relatively specific radiographic presentations
In some cases, dx can be confidently made based on radiographic features alone
Can provide clues about clinical behavior
- Estimate tumor growth rate
- Expansive or infiltrative growth patterns characteristic of locally aggressive and malignant tumors
Modalities:
- Plain Radiograph
- CT
- MRI ⇒ method of choice for local staging
- Bone Scintigraphy ⇒ highly sensitive but relatively non-specific
  - Main role in detection of suspected metastases in the whole skeleton

Question 16

Q

Bone Tumors

Radiologic Features

Answer

A

Radiographic examination should answer the following questions:

Location
Type of bone (flat, tubular)
- If long bone affected ⇒ where lesion is centered
  - Cortex or medulla
  - Epiphysis, metaphysis or diaphysis
Underlying bone abnormality (eg., bone infarct, Paget’s disease)
- High-grade sarcomas tend to arise in damaged bone
Multifocality
- Malignant > benign
- Benign lesions tend to show symmetrical distribution
Well-defined margin, rim of sclerotic bone?
- Presence strongly suggests a benign non-growing or slow growing lesion
Cortical expansion or destruction?
- Findings seen with locally aggressive or malignant tumors
Periosteal reaction and, if so, of what type
Patterns of Mineralization (calcification or ossification)
- Helpful in identification of bone-producing and cartilage producing tumors
Is there a soft tissue mass?

Question 17

Q

Periosteal Reactions

Answer

A

Periosteum responds to traumatic stimuli or pressure from an underlying growing tumor by depositing new bone
Radiographic appearance of response reflects the degree of aggressiveness of the tumor

Question 18

Q

Benign and Non/Slow-Growing

Lesions

Answer

A

Well-circumscribed and shows a geographic pattern of bone destruction with a sclerotic rim
Slow-growing tumors provoke focal cortical thickening ⇒ solid periosteal reaction or “buttress”

Question 19

Q

Rapidly Growing

Lesions

Answer

A

May still show a well-demarcated zone of bone destruction (geographic pattern) but will lack a sclerotic rim
With continued growth, may show cortical expansion
Periosteal reactions include:
- Codman’s triangle ⇒ elevation of periosteum to a significant degree, forming an acute angle
- “Onion-skinning” ⇒ seen in Ewing sarcoma
- Spiculated “hair-on-end” appearance due to periosteal new bone formation

Question 20

Q

Osteoid

Answer

A

Malignant osteoid can be recognized radiologically as cloud-like or ill-defined amorphous densities with haphazard mineralization

Pattern is seen in osteosarcoma

Question 21

Q

Chondroid

Answer

A

Usually easier to recognize cartilage vs osteoid by the presence of focal stippled or flocculent densities, or in lobulated areas, as rings or arcs of calcifications.

Question 22

Q

Bone Tumors

Histologic Evaluation

Answer

A

Most important histologic features to consider:
- Pattern of growth (eg., sheets of cells vs. lobular architecture)
- Cytologic characteristics of the cells
- Presence of necrosis and/or hemorrhage and/or cystic change
- Matrix production
- Relationship between the lesional tissue and the surrounding bone (eg., sharp border vs. infiltrative growth)
Dx of bone tumor requires clinical, radiological, and histologic appearances
Biologically different types of tumors may have overlapping histologic features

Question 23

Q

Osteoid Osteoma

Overview

Answer

A

Benign, bone-producing neoplasm

Small size w/ limited growth potential
Lesional tissue ⇒ “nidus”
- Small radiolucent focus < 1 cm
- Either within the cortex or adjacent to it
Predominantly in males 10-25 y/o
50% of cases in the femur and tibia
- Femoral neck is one of the most common anatomic sites

Question 24

Q

Osteoid Osteoma

Effects

Answer

A

Causes extensive reactive changes in surrounding tissues
Produces prostaglandin/prostocyclin-mediated effects
Induces exuberant, reactive, periosteal sclerosis, soft tissue edema and pain

Question 25

Q

Osteoid Osteoma

Gross Appearance

Answer

A

If nidus removed intact ⇒ circumscribed portion of red, trabecular bone < 1 cm in size
- Either within the cortex or adjacent to it
XR shows a small, intracortical, radiolucent focus (nidus), surrounded by dense reactive periosteal bone

Question 26

Q

Osteoid Osteoma

Microscopic Appearance

Answer

A

Lesional tissue (“nidus”) well-demarcated from the surrounding sclerotic bone

Composed of thin, often interconnected spicules of osteoid and woven bone rimmed by osteoblasts

Osteoclast-like giant cells can be seen

Intervening fibrous stroma shows prominent vascularity

Both osteoblasts and stromal cells are without significant nuclear atypia

Question 27

Q

Osteoid Osteoma

Differential Diagnosis

Answer

A

Osteoblastoma
Intracortical osteosarcoma ⇒ significant nuclear atypia and invasive growth pattern are indicative of malignancy

Question 28

Q

Osteoblastoma

Overview

Answer

A

Larger than 1.5 cm
Slowly and progressively growing neoplasms
Term “aggressive osteoblastoma” is applied to large, locally destructive lesions that mimic a low-grade osteosarcoma on microscopic examination
Peak incidence during 2nd and 3rd decades of life

Question 29

Q

Osteoblastoma

Clinical Behavior

Answer

A

Tend to arise in the axial skeleton
- Involves spine and sacrum in ~ 40% of cases
- 2nd most frequent site is the mandible, followed by other craniofacial bones
Do not produce prostaglandin/prostocyclin-mediated tissue reaction
May grow to a considerable size ⇒ bone expansion and cortical destruction
Recurrences in ~ 20% of cases
No metastases

Question 30

Q

Osteoblastoma

Appearance

Answer

A

Radiology:

XR ⇒ well-circumscribed, low metaphyseal, radiolucent lesion containing matrix-type radiodensities
- No sclerotic rim
Affects long bones and vertebrae

Histology:

Resembles osteoid osteoma
Osteoblasts and osteoclast-like giant cells surround interconnected spicules of osteoid and woven bone
Intervening fibrous stroma shows prominent vascularity
No significant cellular atypia

Question 31

Q

Osteosarcoma

Overview

Answer

A

Malignant tumor composed of neoplastic mesenchymal cells synthesizing osteoid or immature bone.

Presence of malignant osteoid distinguishes an osteosarcoma from other sarcomas
Preferentially affects rapidly growing parts of the skeleton
- Distal femur and proximal tibia (50% of cases)
- Proximal humerus
- Elderly ⇒ tends to involve axial skeleton and flat bones
Metaphysis is the most common site in long bones

Question 32

Q

Osteosarcoma

Epidemiology

Answer

A

Most common primary sarcoma of bone
Bimodal age distribution:
- Peak incidence in 2nd decade of life ⇒ most active skeletal growth
  - < 5% of cases occur in children younger than 10 years
- In the elderly ⇒ usu. seen in association with a pre-existing bone disease
  - Paget’s, radiation osteitis, or bone infarct

Question 33

Q

Osteosarcoma

Classification

Answer

A

Subdivided into:
- Intramedullary (largest group)
- Intracortical
- Surface osteosarcomas
Subclassified into high-grade and low-grade
- Based on the degree of differentiation

Question 34

Q

Osteosarcoma

Appearance

Answer

A

Histologic findings can be extremely variable

Composed of highly pleomorphic cells and haphazard deposits of osteoid
Anaplastic cellular features and mitotic activity
Malignant osteoid:
- Lace-like pattern
- Haphazardly arranged trabeculae of woven bone
± Foci of neoplastic cartilage

May appear identical to MFH ⇒ minimal osteoid production

May contain masses of malignant cartilage or numerous giant cells

Question 35

Q

Osteosarcoma

Histologic Variants

Answer

A

Osteoblastic (≈ 50%)
Chondroblastic
Fibroblastic
Telangietatic
Small cell
Giant cell

Question 36

Q

Osteosarcoma

Disease Course and Treatment

Answer

A

One of the most aggressive and highly lethal tumors
Most powerful predictor of outcome is the histologic response of the tumor to pre-operative chemotherapy
- Tumor necrosis following tx graded according to the following system:
  - Grade 1 - 0-50% necrosis
  - Grade 2 - 51-90%
  - Grade 3 - 91-99%
  - Grade 4 - 100% necrosis
- ≥ 90% tumor necrosis ⇒ nearly 90% 5-year disease-free survival
- < 90% tumor necrosis ⇒ 14% 5-year disease-free survival in pts with
Metastases extremely common
- Usu. to lungs, bones, and liver

Question 37

Q

Osteochondroma

Overview

Answer

A

Cartilage-capped outgrowth attached to the underlying bone by a bony stalk.

Can be solitary or multiple
- Multiple Hereditary Exostosis ⇒ multiple osteochondromas
  - AD hereditary disease
  - More likely to undergo malignant transformation (<1%)
Most common skeletal sites are the metaphyses of long bones
- It does not occur in bones with membranous type of ossification
M:F = 3:1
When skeletal maturity is reached, osteochondromas usually stop growing
- Continued growth may signify malignant transformation
Clonal origin of sporadic & hereditary forms supported by clonal cytogenetic abnormalities
- Deletions of regions q24 of chromosome 8 (EXT1 locus) and p11-12 of chromosome 11 (EXT2 locus) ⇒ inactivation of EXT1 and EXT2 genes

Question 38

Q

Osteochondroma

Appearance

Answer

A

XR ⇒ pedunculated bony outgrowth @ proximal tibial metaphysis
Histology:
- Cortex and medulla are continuous with those of the lesion
- Mature trabecular and cortical bone
- Uniform, cartilaginous cap with stippled calcifications
  - Mature, focally calcified hyaline cartilage
  - < 1 cm thick

Question 39

Q

Chondroma

Overview

Answer

A

Common, benign, intramedullary bone tumor composed of mature hyaline cartilage.

Wide age distribution
Peak incidence during 3rd and 4th decades of life
Limited growth potential
Many lesions remain small and asymptomatic

Question 40

Q

Chondroma

Appearance

Answer

A

Three characteristic features:
- Vague lobularity (“soap bubbles”)
- Abundant cartilaginous matrix
  - Can be focally calcified
- Low cellularity
Clustered and scattered chondrocytes with small, uniform, darkly-stained nuclei
Occasional bi-nucleated chondrocytes present
No mitotic figures

Question 41

Q

Ollier’s Disease

Answer

A

Rare, non-hereditary disorder
Characterized by multifocal proliferation of dysplastic cartilage (enchondromatosis)
Usually dx in children and adolescents between 10 and 20 years of age
Very high risk of malignant transformation (20% - 30%)
- Usually to chondrosarcoma

Question 42

Q

Marfucci’s Syndrome

Answer

A

Multiple cartilaginous tumors associated with hemangiomas

Similar to Ollier’s

Question 43

Q

Enchondromas

Answer

A

Associated with pain and fracture or thinning of the overlying cortex
Long bones ⇒ suspicious for malignancy
Small bones ⇒ no dx of chondrosarcoma unless a tumor permeates into soft tissue

Question 44

Q

Chondroblastoma

Overview

Answer

A

Rare, benign neoplasm
Occurs in the 2nd decade of life (75%) ⇒ growth plates are still open
One of two neoplasms of incompletely differentiated cartilage
- The other neoplasm is chondromyxoid fibroma
70% arise in the proximal humerus and at the knee
- Long bones ⇒ almost always occurs in the epiphysis
Recurrence rate ~ 10% within the bone or in the adjacent soft tissue
It can occasionally produce “benign”, clinically non-progressive lung implants

Question 45

Q

Chondroblastoma

Appearance

Answer

A

Irregular but circumscribed, radiolucent epiphyseal lesion surrounded by reactive bone sclerosis
Highly cellular tumor consisting of sheets of round to polygonal chondroblasts
- Folded or clefted nuclei
- Fine chromatin pattern
- Occasional inconspicuous nucleoli
- Stains ⊕ for S-100
Mitotic activity is low
Multiple small foci of immature bluish-pink chondroid ⇒ vaguely lobular appearance
Multinucleated giant cells scattered throughout lesion
- Are of different cell line and stain ⊕ for histiocytic markers (CD68)
“Chicken-wire” calcification is virtually pathognomonic of chondroblastoma

Question 46

Q

Chondroblastoma

Differential Diagnosis

Answer

A

Giant Cell Tumor (GCT):
- Also occurs @ epiphysis but in skeletally mature individuals
- Lacks chondroid matrix
- ⊖ staining with S-100
Chondromyxoid fibroma:
- Centered in the metaphysis and lacks calcification
Clear cell chondrosarcoma:
- Epiphyseal tumor of pts > 40 y/o
- Malignant chondrocytes and characteristic large cells with clear cytoplasm

Question 47

Q

Chondromyxoid Fibroma

Overview

Answer

A

Benign tumor
Occurs in pts < 40 y/o
Peak incidence is between ages 10 and 20
30% occur at the knee area
Long bones ⇒ involves the metaphysis or meta-diaphysis and is often eccentric
± Secondary aneurysmal bone cyst formation

Question 48

Q

Chondromyxoid Fibroma

Clinical Behavior

Answer

A

Recurrence rate averages 15%-20%

Large or recurrent lesions may be locally aggressive

Question 49

Q

Chondromyxoid Fibroma

Appearance

Answer

A

Well-defined, expansile lytic lesion
Centered at the metaphysis
Bordered by a sclerotic rim
Moderately cellular chondromyxoid tissue with two characteristic features:
- Vague lobularity caused by alternating highly cellular and less cellular areas
  - ↑ Cellularity @ periphery of lobules
- Mildly pleomorphic, angular and stellate cells set in bluish-pink chondromyxoid stroma

Question 50

Q

Chondromyxoid Fibroma

Differential Diagnosis

Answer

A

Chondroblastoma
Chondrosarcoma

Question 51

Q

Chondrosarcoma

Overview

Answer

A

Malignant, cartilage-producing tumor

Patient age is typically 30-50 years
Extremely rare in children ⇒ almost always high grade
- Most chondroid tumors in children and adolescents are chondroblastic osteosarcomas
Common sites:
- Bones of the trunk including the pelvis
- Long bones such as the femur and humerus
Osteochondroma, enchondroma and fibrous dysplasia may undergo malignant transformation into a chondrosarcoma

Question 52

Q

Chondrosarcoma

Appearance

Answer

A

Large, lobulated, ill-defined lesion
Centered in the distal femoral metaphysis
Moderately cellular, lobulated cartilaginous tumor

Question 53

Q

Chondrosarcoma

Clinical Behavior

Answer

A

Aggressiveness predicted by histologic grade.

Based on three parameters:

Cellularity
Degree of nuclear atypia
Mitotic activity

Question 54

Q

Chondrosarcoma

Grade 1

Answer

A

Very similar to enchondroma with higher cellularity and mild cellular pleomorphism
Small nuclei show open chromatin pattern and small nucleoli
Frequent binucleated cells
Mitoses are very rare
Locally aggressive and prone to recurrences but usually do not metastasize

Question 55

Q

Chondrosarcoma

Grade 2

Answer

A

Cellularity higher than Grade 1 tumors
Moderate cellular pleomorphism
- Plump nuclei
- Frequent bi-nucleated cells
- Occasional bizarre cells
Mitoses are rare
± Foci of myxoid change
~ 10% to 15% of Grade 2 chondrosarcomas produce metastases

Question 56

Q

Chondrosarcoma

Grade 3

Answer

A

High cellularity
Marked pleomorphism
↑ N/C ratio
Many bizarre cells
Frequent mitoses (more than 1 per hpf)
These are high grade tumors with significant metastatic potential

Question 57

Q

Non-Ossifying Fibroma (NOF)

Overview

Answer

A

Common, non-neoplastic, self-healing fibrous tissue forming tumor

Occurs in skeletally immature individuals
- Usu. between 5-20 y/o
Small lesions usu. incidental radiological findings
Larger lesions occupying > ½ of bone diameter ⇒ ± pathologic fracture
Usu. a solitary lesion in the metaphysis or meta-diaphysis of the long bone at the knee, distal tibia or proximal humerus
Can resemble GCT
- Epiphyseal location and occurrence in adults

Question 58

Q

Non-Ossifying Fibroma (NOF)

Radiologic Findings

Answer

A

Sharply demarcated, lucent, loculated, meta-diaphyseal lesion surrounded by a rim of sclerotic bone.

Predominantly involves the lateral portion of the bone ⇒ eccentric location
Produces mild cortical expansion
Large lesions can involve the entire diameter of the bone expanding the cortex
Dx by XR alone if located in the typical skeletal site and in appropriate age group

Question 59

Q

Non-Ossifying Fibroma (NOF)

HIstology

Answer

A

Moderately cellular
Uniform spindle cells in a storiform pattern w/ bland appearance
Scattered giant cells
Multiple collections of foamy histiocytes (xanthoma cells)
± Hemosiderin-laden MΦ
Mitotic figures are easily found averaging 4 per 10 hpf
- No atypical mitoses

Question 60

Q

Jaffe-Campanacci

Syndrome

Answer

A

Multiple non-ossifying fibromas & cutaneous cafe au lait spots

Question 61

Q

Benign Fibrous Histiocytoma

Answer

A

Lesions w/ histologic features of NOF but occur in unusual locations
- Pelvis, ribs or vertebrae
Designation controversial and is not generally accepted

Question 62

Q

Fibrous Dysplasia

Overview

Answer

A

Benign fibro-osseous lesion

Considered a hamartoma
Occurs sporadically during the period of skeletal growth (10-25 y/o)
Intramedullary location
Most common locations include the long bones (ribs, femur, tibia, jaw and humerus) in the metaphysis or diaphysis
Hallmark of FD is inability of tissue @ affected site to produce mature lamellar bone
- Arrested @ level of woven bone

Question 63

Q

Fibrous Dysplasia

Types

Answer

A

Two forms:

Monostotic (70% of cases)
Polyostotic
- McCune-Albright syndrome
  - FD, cutaneous café au lait pigmentations, and precocious puberty
- Mazabraud’s syndrome
  - FD in close proximity to soft tissue myxomas

Question 64

Q

Fibrous Dysplasia

Overview

Answer

A

Three characteristic histologic features:
- Thin wavy spicules of woven bone (“Chinese characters”)
- Lack of osteoblastic rimming or osteoclastic activity
- Moderately cellular, bland fibrous background
In children ⇒ stromal mitoses may be frequent (1 to 5 per hpf)
In adults ⇒ mitotic figures are very rare to absent

Answer 59

A

Relatively uncommon, locally aggressive neoplasm

4% of all primary bone tumors
Affects skeletally mature individuals, 20-50 y/o
- Extremely rare in children and patients older than 60 years
Centered in the epiphysis
65% in the distal femur, proximal tibia and distal radius
- May affect any long bone, pelvis, sacrum, and spine (3%)

Answer 60

A

± Bone destruction and soft tissue invasion
Intravascular invasion in 30% of cases
- Not correlated with local aggressiveness or development of pulmonary implants
Common secondary changes:
- Hemorrhage and necrosis
- Fibrohistiocytic (xanthomatous) change
- Aneurysmal bone cyst formation
Complications:
- Pathologic fractures
- Malignant transformation (dedifferentiation)
Local recurrences common if not completely excised (40% - 60%)
- May involve bone and/or soft tissue

Answer 61

A

Radiologic appearance:
- Well-defined, lytic lesion
- Eccentrically located in the distal epiphysis
- Subchondral and metaphyseal extension
Histology:
- Multinucleated giant cells
- Small, ovoid, mononuclear stromal cells
  - Monocyte/MΦ derived
  - Poorly defined cytoplasmic borders and bland nuclei
- Mitoses average 4 per 10 hpf
  - No atypical mitoses
- ± Areas of prominent fibrohistiocytic changes
  - Storiform arrangement of stromal cells
  - Clusters of foamy histiocytes (xanthoma cells)

Answer 62

A

80% of cases occur in pts 5-20 y/o
Most common sites:
- Diaphysis of femur, tibia and humerus
- Pelvis and ribs
  - Askin tumor of the chest if in ribs
Arises in the medullary cavity
- Invades cortex and periosteum
- Fequently produces a soft tissue mass
Positive for CD99/O13
Chromosomal translocation ⇒ EWS-FLI-1 fusion gene

Answer 63

A

Both are “small round blue cell” tumors
Similar neural phenotype
- Positive for CD99/O13
Identical chromosomal translocation
- t(11;22)(q24;q12) → EWS-FLI-1 fusion gene
Degree of neural differentiation distinguishes them from one another:
- EM ⇒ cells are undifferentiated and show prominent glycogen deposits
- PNET ⇒ neural differentiation
  - NSE and/or S100 positive

Answer 64

A

Frequently produces a soft tissue mass
Tumor site is often painful, swollen and warm
Patients may have fever, elevated ESR and leukocytosis mimicking infection

Answer 65

A

Large destructive, diaphyseal lesion
Permeative periosteal reaction of a “hair-on-end” or “onion-skin” type
MRI superior to XR in showing cortical disruption and soft tissue involvement

Answer 66

A

Sheets of primitive cells with little histologic evidence of differentiation
Mitotic rate is relatively low
Positive for CD99/O13 immunostain

Answer 67

A

A common, severe, and debilitating disease
Estimated 15 million symptomatic cases in the U.S. and many more asymptomatic
More common in women, esp. post-menopausal women
Cause is unknown

Answer 68

A

↑ Bone resorption
- Occurs as part of aging
- Especially ↑ in postmenopausal women
↓ Bone formation
Overall organic to mineral matrix balance remains the same
Spicules are smaller, thinner and more fragile
- Bone looks the same histologically
- Much weaker and thinner structurally

Answer 69

A

OP seen in older people

Development of the disease is due to hormonal imbalances that occur in the aged, especially post-menopausal women

Answer 70

A

Hereditary
Osteogenesis imperfecta
Exercise ⇒ ↑ bone mass, ↑ bone density, and ↓ incidence of OP
- Females who exercise to amenorrhea (e.g. long-distance runners) are more susceptible to OP
Bone size ⇒ smaller people at ↑ risk for OP
Greater incidence in whites than blacks
Hormones ⇒ those on steroids lose bone mass and are at risk
Long-term heparin therapy ↑ risk of OP

Answer 71

A

↓ Structural integrity ⇒ fractures

Most common sites of thinning due to OP:

Neck of femur
Vertebral column
- Normal thickness
- Microfractures d/t thinning of the bone
- Can result in fracture of the spine & collapse of vertebral column
Metacarpals

Answer 72

A

Best way to dx OP is by dual photon beam densitometry
Blood levels of calcium, phosphorus, and alkaline phosphatase will be normal
XRs will also be normal

Answer 73

A

Tx with estrogens, ↑ calcium, and calcitonin injections.

Estrogens given to ↓ bone loss
- ↑ Risk of endometrial carcinoma in post-menopausal woman
- ? ↑ risk of breast cancer
Calcitonin shown to be successful in tx of OP

Answer 74

A

Most common remedial bone disease of the elderly
Due to Vit D deficiency
- Usu. d/t poor diet in the elderly
- Also seen in underdeveloped countries d/t poverty and poor diet
Inadequate calcium absorption d/t ↓ Vit D
Widened organic matrix that is not mineralized

Answer 75

A

Bending, bowing, and breaking of bones
Overabundance of organic matrix
- Matrix is not mineralized
  - Normal bone takes 6-10 days to mineralize
  - In OM, it takes 2-3 months to mineralize

Answer 76

A

↓ Phosphorus
Calcium is low to low normal
↑ Bone turnover ⇒ ↑ alkaline phosphatase
Biopsy: widening of osteoid seams

Answer 77

A

“Osteitis Deformans”

Affects 3% of the population
Primarily a disease of the elderly (seen after age 40-50)
- By age 90, it affects 10% of males and 15% of females

Answer 78

A

Monostotic (15% of cases)
- Occurs at a single site
- Most common site is the tibia
Polyostotic (85% of cases)
- Occurs at multiple sites
- Most common sites include the spine and pelvis

Answer 79

A

Osteolytic stage
- Osteoclast ⊕ by virus and resorbs bone
  - Bone digestion ⇒ ↑ fibrous tissue and vascularity between the bony spicules
- Can cause red hot skin over the bone
- ↑ Vascularity ⇒ ± high out cardiac failure
Osteolytic / osteoblastic stage
- Continued bone lysis
- ↑ osteoblastic activity ⇒ ↑ bone formation
  - Balance b/t lysis & formation abnormal
  - Resulting bone is not in normal Haversian canal structure
  - Abnormal mineral deposition patterns
- Mosaic pattern is pathognomonic for Paget’s

Answer 80

A

Believed to be caused by an infection of the osteoclast by a Paramyxovirus
Thick bone made w/ poor structural integrity ⇒ deformity & fracture
↑ Osteoblastic activity ⇒ osteogenic sarcoma in 1-10% of pts
- Longer disease duration ⇒ ↑ likelihood of eventually developing osteogenic sarcoma
Rapid rate of bone turnover called Matrix Metabolic Madness

Answer 81

A

Highest levels of alkaline phosphatase of any bone disease
Most pts asymptomatic
- Incidental findings on XR
Some pts present w/ pain or bone deformity
Skeletal changes:
- Thickening of arms, tibia, femur, pelvis, and clavicles
- Skull is also thickened but d/t loss of integrity and nl structure, if you fill the skull with water it will leak like a sieve

Answer 82

A

Closed fracture (simple)
- Skin intact
- Complete vs incomplete (greenstick)
- Stable fracture ⇒ broken ends line up and are barely out of place
Comminuted fracture
- Bone shatters into three or more splintered spicules
Compound fracture (open)
- Penetrates skin
- Most serious due to potential for infection

Answer 83

A

Healing occurs in 4 stages:

Hematoma formation
- Blood clot @ site of fx
Soft callus formation
- ⊕ collagen production @ ends of the bone ⇒ fibrous procallus (10-14 days)
  - Fracture stable but weak
  - Poor immobilization ⇒ shearing forces ⇒ abnormal collagen formation
  - Comminuted fx ⇒ splinters can stop formation of fibrous and cartilaginous tissue
  - Comminuted and compound fx ⇒ soft tissue invasion can delay collagen deposition and healing
- Chondrocytes start to form cartilage ⇒ cartilaginous procallus
  - Poor immobilization ⇒ ± pseudoarthrosis
    - Joint space w/o cartilage or bone formation ⇒ insufficient healing
Hard callus formation
- Immature spongy bone deposited onto cartilage matrix
Bone remodeling
- Lamellar bone deposition

Answer 84

A

Malalignment
Comminution w/ bone spicules at fracture site
Inadequate immobilization
Infection ⇒ prevents healing from taking place